'Bertram' was a British tactical cover and deception plan to conceal the build-up of Lieutenant General B. L. Montgomery’s 8^th Army before the 2^nd Battle of El Alamein (October/November 1942).

The plan was conceived by Colonel Dudley W. Clarke, who was then called to Washington to work on the cover plans for 'Torch', so implementation was left to Lieutenant Colonel C. Richardson of the 8^th Army’s operations staff.

In the months preceding 'Lightfoot', the British undertook several deception activities in an effort to sow confusion the Axis leadership in North Africa about the location and timing of the forthcoming battle. In September, for example, men of the 8^th Army and their supporting elements dumped waste materials such as emptied packing cases under camouflage nets in the northern sector to simulate dumps for ammunition and rations. Axis reconnaissance spotted and reported these but, as no offensive action immediately followed and the supposed dumps did not change in appearance, the Axis leadership then ignored them.

This allowed the 8^th Army then to increase its stocks of forward-located supplies, wholly unrealised by the Axis leadership, by the simple expedient of replacing the rubbish with ammunition, petrol or rations at night. A dummy pipeline was also built in the hope that this would persuade the Axis leadership to conclude that the British offensive would take place later and somewhat farther south than in fact it did. Further deceptive measures included 'tanks' (canvas-covered plywood frames placed over Jeeps) which were made and deployed in the south, and the disguising of real tanks, destined for the battle in the north, as supply trucks by the fitting of removable plywood superstructures over them.

Subsidiaries of 'Bertram' were 'Brian', 'Canwell', 'Diamond', 'Martello', 'Melting Pot', 'Munassib' and 'Murrayfield', and the associated strategic plan was 'Treatment'.

The 'story' peddled by 'Bertram' was that Montgomery had decided to postpone his offensive from its planned date of 23 October to a time in November as there were problems with the M4 Sherman medium tanks recently delivered from the USA, and that when the British offensive began it would comprise a feint in the north and then the main assault in the south, which was exactly the opposite of what Montgomery planned.

Montgomery had three corps in the form of Lieutenant General H. Lumsden’s X Corps, Lieutenant General B. G. Horrocks’s XIII Corps and Lieutenant General Sir Oliver Leese’s XXX Corps. The right (northern) wing was held by the XXX Corps and the left (south) wing by the XIII Corps, and behind these was the newly created X Corps. Montgomery’s plan was for the XXX Corps to drive two gaps into the Axis left wing through which Major General A. H. Gatehouse’s 10^th Armoured Division and Major General R. Briggs’s 1^st Armoured Division of the X Corps would pass, while in the south the XIII Corps would punch a single hole, clearing the way for Major General J. Harding’s 7^th Armoured Division of the XIII Corps to penetrate the Axis front and do all that it could to divert Rommel’s attention from his left wing.

The goal of 'Bertram' was therefore was to ensure that the Axis armour on Rommel’s southern wing, about half of what the Axis forces could muster, remained there. The key was to keep the Germans from learning that the X Corps was being positioned in the north behind the XXX Corps. Dumps behind the XXX Corps' front to support the main attack were created at night and camouflaged as vehicle parks and camps during the day. Then, beginning on 6 October, a great vehicle concentration (4,000 real machines and 1,200 fake machines) was accumulated behind the lines in the north, and some 1,600 more vehicles were gathered at a staging area behind the centre of the line. The object of these concentrations was to accustom the Axis forces to the sight of very large numbers of transport vehicles in these locations. At the same time a fake concentration was started behind the front of the XIII Corps in the south.

A dummy water pipeline, together with simulated pump houses and reservoirs, was also laid across 20 miles (32 km) of desert in 'Diamond'. The work moved at a rate designed to lead Axis observers to calculate that it could not be finished before a time early in November. Dummy supply dumps were built, together with dummy camps and associated bogus transport, field kitchens and the like in 'Brian'. In a rare double bluff, obvious dummy guns were emplaced, subsequently ostentatiously replaced by real pieces of artillery, in 'Munassib'.

What was apparently a staging area for the 10^th Armoured Division was laid out behind the southern wing.

The main concentration began on 18 October. One at a time the armoured brigades of the X Corps were surreptitiously moved to the northern assembly area, where the tanks and guns were covered with 'Sunshields' and 'Cannibals', replacing real vehicles and dummies in the bogus vehicle pool in a manner that would go unnoticed by Axis reconnaissance. This started with the movement of an armoured brigade of the 1^st Armoured Division to a staging area behind the centre of the line, which it remained in full view for a day. That night the brigade moved to the north and was replaced by another brigade of the same division, which in turn remained in full view for a day and appeared to the Axis forces to be the same brigade as before. A third brigade, with division headquarters, moved out and exchanged places with the dummy motor pool that had been planted behind the centre a few weeks earlier.

On the same date, 19 October, the 10^th Armoured Division moved to its staging area in the south. By that evening, therefore, Axis reconnaissance would see that a new armoured division had taken up a position in the south and a new armoured brigade in the centre. Over the next two nights the two remaining brigades of 1^st Armoured Division and the whole of the 10^th Armoured Division moved to the north, where 'Sunshields' and 'Cannibals' converted them seemingly into ordinary transport in 'Martello'. The real and dummy vehicles replaced by the tanks and guns of the 1^st Armoured Division in turn replaced them behind the centre in 'Murrayfield', and the 10^th Armoured Division was replaced in the south by a huge display of dummy machines, including Colonel Jones’s entire dummy armoured brigade, in 'Melting Pot'.

Meanwhile, over a period of four weeks the elaborate 'Canwell' radio deception plan had simulated the communications net of 10^th Armoured Division, and this opened in full voice on 20 October with the 'Melting Pot' dummies, using 25 transmitters to mimic the tactical headquarters of the 8^th Army and the headquarters of a corps, two divisions, and five brigades.

On 23 October, the day on which the 2^nd Battle of El Alamein began in 'Lightning', the Axis forces therefore believed that Montgomery had one armoured division in a holding area 25 miles (40 km) from the southern end of the front and another some 40 miles (65 km) behind the centre, and no armour in the north.